In order to determine the efficacy of using data from 96-h acute bioassays for predicting toxicity associated with shorter exposure periods, a series of static, dynamic, and plug-flow bioassays were performed using bluegill as test organisms. Test chemicals included acrylonitrile, ammonia, chlorobenzene, chromic acid, copper sulfate, 2-ethoxyethylacetate, methylmethacrylate, sodium hydroxide, sulfuric acid, and xylene. Exposure durations ranged from 1 to 96 h. Regression techniques were used to develop time-toxicity curves to determine how well short-term toxicity could be predicted by 24 to 96 h data.

The results from these experiments indicate that data from 24 to 96-h exposure periods have limited use in predicting toxicity associated with shorter exposure periods, depending on the desired level of precision of the estimate. In extreme cases, the estimated LC50s ranged from twenty-fold below to three-fold above the observed LC50 values. In most cases, however, agreement between the estimated and actual LC50 values was much closer. While the usefulness of such mathematical predictors remains to be established, they could have merit in assessing the potential toxicity associated with single-event exposures such as chemical spills or runoff events.